#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<class t> using vc = vector<t>;
template<class t> using vvc = vc<vc<t>>;
using pi = pair<int,int>;
using pl = pair<ll,ll>;
using vi = vc<int>;
using vvi = vvc<int>;
using vl = vc<ll>;
using vvl = vvc<ll>;

#define rep(i,a,b) for (int i = (int)(a); i < (int)(b); i++)
#define irep(i,a,b) for (int i = (int)(a); i > (int)(b); i--)
#define all(a) a.begin(),a.end()
#define print(n) cout << n << '\n'
#define pritn(n) print(n)
#define printv(n,a) {copy(all(n),ostream_iterator<a>(cout," ")); cout<<"\n";}
#define printvv(n,a) {for(auto itr:n) printv(itr,a);}
#define rup(a,b) (a+b-1)/b
#define input(A,N) rep(i,0,N) cin>>A[i]
#define chmax(a,b) a = max(a,b)
#define chmin(a,b) a = min(a,b)

//const ll mod = 998'244'353;
const ll mod = 1'000'000'007;
//const ll mod = 67'280'421'310'721;
struct mint{
    long long x;
    mint(long long x=0):x((x%mod+mod)%mod){}
    mint operator-() const{
        return mint(-x);
    }
    mint& operator+=(const mint& a){
        if((x+=a.x)>=mod)x-=mod;
        return *this;
    }
    mint& operator-=(const mint& a){
        if((x+=mod-a.x)>=mod)x-=mod;
        return *this;
    }
    mint& operator*=(const  mint& a){
        (x *= a.x) %= mod;
        return *this;
    }
    mint operator+(const mint& a) const{
        mint res(*this);
        return res+=a;
    }
    mint operator-(const mint& a) const{
        mint res(*this);
        return res-=a;
    }
    mint operator*(const mint& a) const{
        mint res(*this);
        return res*=a;
    }
    mint pow(long long n) const {
        assert(0 <= n);
        mint a = *this, r = 1;
        while (n) {
            if (n & 1) r *= a;
            a *= a;
            n >>= 1;
        }
        return r;
    }
    mint inv() const{
        return pow(mod-2);
    }
    mint& operator/=(const mint& a){
        return (*this)*=a.inv();
    }
    mint operator/(const mint& a) const {
        mint res(*this);
        return res/=a;
    }
    friend ostream& operator<<(ostream& os, const mint& m){
        os << m.x;
        return os;
    }
    bool operator==(const mint& a) const {
        return x == a.x;
    }
    bool operator<(const mint& a) const{
        return x < a.x;
    }
};


int main(){
    cout << fixed << setprecision(15);
    
    int n;
    cin>>n;
    vvc<mint> dp(n+1,vc<mint>(3,0));
    dp[0][0] = mint(1);

    for(int i = 0;i<n;i++){
        dp[i+1][1] += dp[i][0];
        dp[i+1][2] += dp[i][1];
        dp[i+1][0] += dp[i][1] + dp[i][2];
    }
    print(dp[n][0]+dp[n][1]+dp[n][2]);
    
    //system("pause");
    return 0;
}